Park H S, Park H J
Department of Physiology, Hallym University, Chunchon and College of Medicine, Konyang University, Nonsan, Korea.
J Korean Med Sci. 2000 Aug;15 Suppl(Suppl):S24-6. doi: 10.3346/jkms.2000.15.S.S24.
Since GABA and its related enzymes had been determined in beta-cells of pancreas islets, effects of GABA on pancreatic exocrine secretion were investigated in the isolated perfused rat pancreas. GABA, given intra-arterially at concentrations of 3, 10, 30 and 100 microM, did not exert any influence on spontaneous or secretin (12 pM)-induced pancreatic exocrine secretion. However, GABA further elevated cholecystokinin (10 pM)-, gastrin-releasing peptide (100 pM)- or electrical field stimulation-induced pancreatic secretions of fluid and amylase, dose-dependently. The GABA-enhanced CCK-induced pancreatic secretions were completely blocked by bicuculline (10 microM), a GABAA receptor antagonist but not affected by saclofen (10 microM), a GABA(B) receptor antagonist. The enhancing effects of GABA (30 microM) on CCK-induced pancreatic secretions were not changed by tetrodotoxin (1 microM) but partially reduced by cyclo-(7-aminoheptanonyl-Phe-D-Trp-Lys-Thr[BZL]) (10 microM), a somatostatin antagonist. In conclusion, GABA enhances pancreatic exocrine secretion induced by secretagogues, which stimulate enzyme secretion predominantly, via GABA(A) receptors in the rat pancreas. The enhancing effect of GABA is partially mediated by inhibition of islet somatostatin release. GABA does not modify the activity of intrapancreatic neurons.
由于已在胰岛β细胞中测定了γ-氨基丁酸（GABA）及其相关酶，因此在离体灌注大鼠胰腺中研究了GABA对胰腺外分泌的影响。以3、10、30和100微摩尔浓度动脉内给予GABA，对自发或促胰液素（12皮摩尔）诱导的胰腺外分泌没有任何影响。然而，GABA剂量依赖性地进一步提高了胆囊收缩素（10皮摩尔）、胃泌素释放肽（100皮摩尔）或电场刺激诱导的胰腺液体和淀粉酶分泌。GABA增强的胆囊收缩素诱导的胰腺分泌被GABAA受体拮抗剂荷包牡丹碱（10微摩尔）完全阻断，但不受GABAB受体拮抗剂赛氯芬（10微摩尔）影响。GABA（30微摩尔）对胆囊收缩素诱导的胰腺分泌的增强作用不受河豚毒素（1微摩尔）影响，但被生长抑素拮抗剂环（7-氨基庚酰基-苯丙氨酸-D-色氨酸-赖氨酸-苏氨酸[BZL]）（10微摩尔）部分降低。总之，GABA通过大鼠胰腺中的GABAA受体增强主要刺激酶分泌的促分泌剂诱导的胰腺外分泌。GABA的增强作用部分由抑制胰岛生长抑素释放介导。GABA不改变胰腺内神经元的活性。
